Two phase system for enclosure systems

ABSTRACT

A coolant management unit includes a server supply manifold, a server return manifold, a power distribution, and a controller. A server supply manifold is to receive cooling fluid from a cooling fluid source. The server supply manifold is to distribute the cooling fluid to server blades. The server return manifold is to receive vapor from the one or more server blades. The cooling fluid is two-phase cooling fluid to extract heat from one or more servers and to evaporate into the vapor into the server return manifold, and the vapor is transmitted to an external condenser via the rack return manifold to be condensed back to a liquid form. A power distribution bus is configured to distribute power to the one or more servers. A controller is configured to control a fluid pump coupled to the server supply manifold based on one or more signals received from different sensors.

FIELD OF THE INVENTION

Embodiments of the present invention relate generally to the server andrack design, cooling hardware, two phase cooling, cooling system,two-phase immersion system. More particularly, embodiments of theinvention relate to a two-phase system for enclosure blade systems.

BACKGROUND

Cooling is a prominent factor in a computer system and data centerdesign. The number of high performance electronics components such ashigh performance processors packaged inside servers has steadilyincreased, thereby increasing the amount of heat generated anddissipated during the ordinary operations of the servers. Thereliability of servers used within a data center decreases if theenvironment in which they operate is permitted to increase intemperature over time. Maintaining a proper thermal environment iscritical for normal operations of these servers in data centers, as wellas the server performance and lifetime. It requires more effective andefficient cooling solutions especially in the cases of cooling thesehigh performance servers.

Heat removal is a prominent factor in a computer system and data centerdesign. The number of high performance electronics components such ashigh performance processors packaged inside servers have steadilyincreased, thereby increasing the amount of heat generated anddissipated during the ordinary operations of the servers. Thereliability of servers used within a data center decreases if theenvironment in which they operate is permitted to increase intemperature over time. Maintaining a proper thermal environment iscritical for normal operations of these servers in data centers, as wellas the server performance and lifetime. It requires more effective andefficient heat removal solutions especially in the cases of coolingthese high performance servers.

The previous solutions for thermal management design for servers are aircooling based, however, the shortfall is that this solution may notsatisfy for high power density systems thermal management since aircooling may reach a limitation for high heat density systems.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are illustrated by way of example and notlimitation in the figures of the accompanying drawings in which likereferences indicate similar elements.

FIG. 1 shows a front view of a two-phase module design according to anembodiment of the application.

FIG. 2 shows a side view of a two-phase module design according to anembodiment of the application.

FIG. 3 shows a top view of a rack design according to certainembodiments of the application.

FIG. 4 shows a rear view of rack integration according to an embodimentof the application.

FIG. 5 shows a perspective view of a system according to an embodimentof the application.

FIG. 6 is a block diagram illustrating an example of an electronic rackaccording to one embodiment.

DETAILED DESCRIPTION

Various embodiments and aspects of the inventions will be described withreference to details discussed below, and the accompanying drawings willillustrate the various embodiments. The following description anddrawings are illustrative of the invention and are not to be construedas limiting the invention. Numerous specific details are described toprovide a thorough understanding of various embodiments of the presentinvention. However, in certain instances, well-known or conventionaldetails are not described in order to provide a concise discussion ofembodiments of the present inventions.

Reference in the specification to “one embodiment” or “an embodiment”means that a particular feature, structure, or characteristic describedin conjunction with the embodiment can be included in at least oneembodiment of the invention. The appearances of the phrase “in oneembodiment” in various places in the specification do not necessarilyall refer to the same embodiment.

The information technology (IT) hardware industry is a critical marketfor many reasons: it plays a crucial role in business competitiveness,service quality and availability, and also plays a significant role inthe infrastructure total cost of ownership (TCO). IT hardware is closelylinked with the profit of an organization. It is one of the corecompetencies of the internet giant, cloud computing service providers,as well as high performance computing and artificial intelligence (AI)computing related business service users and providers who build,operate, compute, store and manage other IT hardware platforms (e.g.,servers) and infrastructures.

The majority of the hyper-scale owners are customizing full-stacks ofthese hardware systems. For instance, in the rapidly growing cloudcomputing business, the performance and cost (both capital cost andoperation cost) of computing and storage hardware systems, clusters andinfrastructure, all require the service providers to create customizedsystems that fit their individual needs the best. These markets requirecontinuous innovation. An efficient system design and operation benefitsthe service providers in multiple aspects in a long term. The key tothis is to develop continuously with more resilience, efficiency,interoperable and cost effective solutions and architectures.

The present disclosure aims to provide a design and system for two-phasecooled blade servers. The present disclosure also can be used fordesigning thermal management solutions for liquid cooled nodes which arepopulated in parallel on the rack. This design aims to solve two-phasebased high power density blade servers' thermal management challenges aswell as hyper scale deployment challenge. In addition, the followingitems serve as additional challenges that the present disclosure aims tosolve: high power density servers; high efficiency operation andmanagement; enable two phase thermal management technology; efficienttwo phase coolant management; designed for high variations in both thecooling capacity and heat load generations; modular design for easyconfigurations for accommodating different use cases; accommodatedifferent rack architectures; cooling capacity reconfigurable; built incontrol strategy for fluid management as well as optimization; andaccommodate different facility architectures.

In addition, the present disclosure also aims to enable to design highheterogeneous rack system with different blade servers coexisting on asingle rack for edge computing applications.

The present application includes a coolant management unit, alsoreferred to as a two-phase module (TPM), which is used for adapting ablade IT system and a rack system. In an embodiment, thetwo-phase/coolant management unit includes single-phase and two-phasecoolant management manifolds and the manifolds are assembled withsub-ports and ports on the opposite sides. In an embodiment, thesub-ports are designed for individual blade servers and an opposite portis for connecting with the main source, including the rack liquid supplymanifold and rack main return manifold. In an embodiment, the powerdistribution bus is integrated within the module. In an embodiment, abuilt-in controller is used for operating the fluid pump assembledbetween the rack liquid supply manifold and the server supply manifold.For example, there are three types of sensors which are the pressuresensor, power meter and leakage detection sensor which are used forcontroller to adjust the operation of the pump. In addition, in anembodiment, the controller includes a communication port used forconnecting with the rack management controller (RMC) which receivesindividual server internal temperature.

In an embodiment, the coolant management unit includes a server supplymanifold, a server return manifold, a power distribution bus, and acontroller. In an embodiment, a server supply manifold is to be coupledto a rack supply manifold to receive cooling fluid from a cooling fluidsource. The server supply manifold is to distribute the cooling fluid toone or more server blades of the server chassis. The coolant managementunit is positioned on a rear side of the server chassis.

In an embodiment, a server return manifold is to be coupled to a rackreturn manifold. In an embodiment, the server return manifold is toreceive vapor from the one or more server blades. The cooling fluid istwo-phase cooling fluid to extract heat from one or more servers and toevaporate into the vapor into the server return manifold. /The vapor istransmitted to an external condenser via the rack return manifold to becondensed back to a liquid form.

In an embodiment, a power distribution bus is configured to distributepower to the one or more servers. A controller is configured to controla fluid pump coupled to the server supply manifold based on one or moresignals received from one or more sensors. For example, the one or moresensors include a pressure sensor coupled to the server return manifold.The sensors include a leakage sensor to detect leakage. In anembodiment, the one or more sensors include a pressure sensor coupled tothe server return manifold. In an embodiment, the one or more sensorsinclude one or more temperature sensors to measure corresponding servertemperature.

In an embodiment, the controller is coupled to a communication portconnected with a rack management controller (RMC). In an embodiment, theRMC receives information of the corresponding server temperature fromthe controller.

In an embodiment, the server supply manifold includes a liquid portconnected with the rack supply manifold. The server supply manifoldincludes one or more liquid sub-ports connected with correspondingliquid ports of the one or more server blades. The server returnmanifold includes a vapor port connected with the rack return manifold.

In an embodiment, the server return manifold includes one or more vaporsub-ports connected with corresponding vapor ports of the one or moreserver blades. In an embodiment, the server return manifold is disposedabove the server supply manifold.

In an embodiment, the power distribution bus is positioned under theserver return manifold. In an embodiment, the server supply manifold ispositioned under the power distribution bus. In an embodiment, thecoolant management unit includes a first blocking panel, a secondblocking panel and a third blocking panel to prevent impact from leakedfluid.

In an embodiment, the first blocking panel is on the top of the coolantmanagement unit, wherein the first blocking panel is inserted into theserver chassis to prevent and segregate any of the leaked fluid from thetop. In an embodiment, the second blocking panel is positioned betweenthe power distribution bus and the server supply manifold to segregateany leakage from connectors with the power distribution hardware. In anembodiment, wherein the third blocking panel is on the bottom of thecoolant management unit, wherein the third blocking panel is insertedinto the server chassis to prevent internal leaked fluid travelingoutside.

According to another aspect, a server chassis includes one or moreserver blades connected with a coolant management unit. For example, thecoolant management unit for connecting the server chassis for liquidcooling further includes a server supply manifold, a server returnmanifold, a power distribution bus, and a controller, as describedabove.

According to a further aspect, an electronic rack includes a pluralityof server chassis arranged in a stack, each server chassis to receiveone or more server blades; and a plurality of coolant management unitscorresponding to the plurality of server chassis for connecting theplurality of server chassis for liquid cooling. In an embodiment, eachcoolant management unit further includes a server supply manifold, aserver return manifold, a power distribution bus, and a controller, asdescribed above.

FIG. 1 shows a front view of a coolant management unit 100 according toan embodiment of the application. In an embodiment, the rack supplymanifold 101 and the rack return manifold 103 are rack based units whichare not considered as the coolant management unit (also referred to as atwo phase module or TPM). In particular, FIG. 1 shows the design of thecoolant management unit (i.e., two-phase module). For example, thetwo-phase module functions as a rack mounted unit for managing anddistributing cooling source and power to the individual blade servers.In an embodiment, the design may have more than one TPMs populated onthe rack for different stacks of blade servers. The coolant managementunit can be mounted on an electronic rack and includes a rack interfaceconnected to rack manifolds via flexible hoses. The server side, thecoolant management unit includes various server interfaces, such asblind mated dripless connectors, which can be used to connect with thecooling modules of server blades of a server chassis.

The coolant is supplied to the cooling devices of a server blade via theserver supply manifold of the coolant management unit. A cooling devicecan be a cold plate attached to an electronic device (e.g., a processor)to extract the heat generated from the electronic device. When thetemperature of the coolant arises above a predetermined threshold (e.g.,its corresponding boiling point), the coolant transforms from a liquidform into a vapor. The vapor then exits the cooling devices of theserver blade into the server return manifold of the cooling managementunit.

In an embodiment, referring to FIG. 1 , the internal design of theTPM/coolant management unit includes three systems, which are the fluidsystem, power system and control system. In an embodiment, for the fluidsystem, the key units are the vapor return manifold (i.e., server returnmanifold 107) and the supply manifold (i.e., server supply manifold105). For example, on the two manifolds (105, 107), the connectors areattached onto them. In an embodiment, there are sub-vapor ports (e.g.,115) on one side, and there is a vapor port 113 on the other side of thevapor return manifold 107.

In an embodiment, for supply manifold 105, the liquid sub-ports (e.g.,111) are on one side (e.g., the side facing the frontend of the rack),which can be used to connect with one or more server blades insertedfrom the frontend of the rack. The opposite side (e.g., the side facingthe backend of the rack) includes liquid port or connector 109, whichcan be connected to rack supply manifold 101, for example, via aflexible hose. In an embodiment, the sub-vapor ports (e.g., 115) andliquid sub-ports (e.g., 111) are facing the frontend of the rack wherethe server blades will be inserted. In an embodiment, these ports orconnectors are used for connecting with the corresponding ports orconnectors on the server blades.

In an embodiment, server return manifold 107 includes a vapor port orconnector 113 that can be used to connect with rack return manifold 103.Server return manifold 107 includes an array of vapor sub-ports orconnectors, such as sub-ports 115. The sub-ports can be used to connectwith the server blades to receive the coolant in the form of vapor fromthe cooling modules (e.g., cold plates) of the server blades. In anembodiment, vapor port 113 is disposed on the side of the coolantmanagement unit that faces the backend of the rack, while the sub-portsare disposed on the opposite side (e.g., the side facing the frontend ofthe rack). The liquid sub-ports and vapor sub-ports may be implementedusing blind mated dripless connectors, such that, a server blade canslide into and remove from a corresponding server slot to connect withor disconnect from the coolant management unit.

In an embodiment, the connection of the vapor port 113 and the mainreturn (i.e., rack return manifold 103) are through a manual matingconnector, for example, using flexible hoses. In an embodiment, theconnection of the liquid port 109 and the liquid supply (i.e., racksupply manifold 101) are through a manual mating connector, for example,using flexible hoses. In addition, in an embodiment, a pressure sensor125 is used on the loop between the main return (i.e., rack returnmanifold 103) and the vapor port 113. In an embodiment, a liquid pump121 is assembled between the liquid supply (i.e., rack supply manifold101) and the liquid port 109. In an embodiment, the main return 103 andliquid supply 101 are the two units will be added to the coolantmanagement unit in one design. In an embodiment, these two units are onone side of the coolant management unit and it is designed only to beadded to the rack once the coolant management units are populated. Inanother embodiment, it can be seen that these two units do not includedas coolant management unit.

In an embodiment, the coolant management unit further includes a powerdistribution bus 129, which is used for providing power to theindividual blade nodes. In an embodiment, the power distribution bus 129includes a main power connector to receive power a rack powerdistribution bus mounted on the rack. Power distribution bus 129 furtherincludes an array of server power connectors to distribute the power tothe server blades. In an embodiment, a power sensor 123 annotated as “E”are added on the system as well. The power sensor 123 is used to detectwhether power has been receive and sufficient to provide power to othercomponents in the server chassis.

In an embodiment, the controller 117 inside the coolant management unitis used for controlling the fluid pump 121 mainly. For example, thecontroller 117 receives signals from the pressure sensor 125, powersensor 123 as well as the leakage sensor 119 to control the operation ofthe pump 121, including the operating speed as well as on and off ofpump 121. In addition, is the coolant management unit further includes acommunication port coupled with controller 117, which allows controller117 to communicate with a rack manage controller (RMC) of the rack, suchas, for example, determining the temperatures of the correspondingserver blade.

It should be noted that the current design shows a rear view of thecoolant management unit, however, the actual layout may not representthe actual unit corresponding locations. For example, FIG. 1 onlyrepresents the system schematic design. That is, the detailed locationof each of the unit may be different as shown in FIG. 1 . For example,FIG. 1 shows the return manifold 103 is above the supply manifold,however, the actual product may consider the return manifold 103 locateddirectly on top of the supply manifold 101 from a top view.

In an embodiment, a coolant management unit is positioned on a rear sideof the server chassis for connecting a server chassis for liquidcooling. Further in an embodiment, a coolant management unit includes aserver supply manifold 105, a server return manifold 107, a powerdistribution bus 129, and a controller 117.

In an embodiment, a server supply manifold 105 is coupled to a racksupply manifold 101 to receive cooling fluid from a cooling fluidsource. For example, the server supply manifold 105 is to distribute thecooling fluid to one or more server blades of the server chassis.

In an embodiment, a server return manifold 107 to be coupled to a rackreturn manifold 103. For example, the server return manifold 107 is toreceive vapor from the one or more server blades. Further, in anembodiment, the cooling fluid is two-phase cooling fluid to extract heatfrom one or more servers and to evaporate into the vapor into the serverreturn manifold 107. Further, in an embodiment, the vapor is transmittedto an external condenser via the rack return manifold 103 to becondensed back to a liquid form. In an embodiment, a power distributionbus 129 is to distribute power to the one or more servers.

In an embodiment, a controller 117 to control a fluid pump 121 coupledto the server supply manifold 105 based on one or more signals receivedfrom one or more sensors (e.g., 119, 123, 125). For example, the one ormore sensors include a pressure sensor 125 coupled to the server returnmanifold 107 to detect the pressure level of the vapor. The sensors mayinclude a leakage sensor 119 to detect leakage. The sensors may includea power sensor 123 coupled to the power distribution bus 129. Thesensors may further include one or more temperature sensors to measurecorresponding server temperature.

In an embodiment, the controller 117 is coupled to a communication portconnected with a rack management controller (RMC). For example, the RMCreceives information of the corresponding server temperature from thecontroller 117.

In an embodiment, the server supply manifold 105 includes a liquid port109 connected with the rack supply manifold 101. In an embodiment, theserver supply manifold 105 includes one or more liquid sub-ports 111connected with corresponding liquid ports of the one or more serverblades. In an embodiment, the server return manifold 107 includes avapor port 113 connected with the rack return manifold 103. In anembodiment, the server return manifold 107 includes one or more vaporsub-ports 115 connected with corresponding vapor ports of the one ormore server blades. In an embodiment, the fluid pump 121 is connected tothe liquid port 109, and the other end of the fluid pump loop isequipped with a fluid connector 127 for connecting with the rack fluidconnectors 133 on the rack supply manifold 101. In an embodiment, thepressure sensor 125 is connected to the vapor port 133, and the otherend of the fluid pump loop is equipped with a vapor connector 131 forconnecting with the rack return manifold 103.

FIG. 2 shows a side view of a coolant management unit design 200according to an embodiment of the application. In particular, FIG. 2shows the design 200 including the coolant management unit and its keystructural units for reliability enhancement. In an embodiment, thefigure in FIG. 2 shows that the blocking panels (201, 203, 205) are usedpackaged on coolant management unit 207. In an embodiment, those panels(201, 203, 205) are designed for preventing impact from any leakedfluid. For example, since coolant management unit 207 will be installedon top of each other in a rack, the impact of the fluid leakage shouldbe considered.

In an embodiment, the corresponding panel design enables a simple andeffective solution for preventing potential fluid. For example, theblocking panel I 201 and III 203 are inserted into the blade chassis 209and panel I 201 is used for preventing fluid from the top of systems andblocking panel II 203 is used for preventing the internal leaked fluidtraveling outside. That is, each of the TPM (e.g., 207) provides adouble protection on any potential leakage. In addition, there is ablocking panel II 203 added to the middle between the power distributionbus 129 and the liquid distribution supply 205. In an embodiment, thisdesign is to enable a segregation of the power and liquid fluid. In anembodiment, there is no segregation between the vapor return manifold103 and the power distribution bus 129, since the vapor may not causedamage to the power bus 129 even there is a leakage. That is, it can beseen that the blocking panel II 203 are used for preventing a largeleakage such as a liquid splash from the connectors or connectionsbetween the connectors.

It can be seen that the block panels I 201 and III 205 can be customizedfor different blade servers and it can be used to create a fullycontained environment of the TPM 207 and the corresponding bladeservers.

In an embodiment, the server return manifold 107 is on top of the serversupply manifold 105. In an embodiment, the power distribution bus 129 ispositioned below the server return manifold 107. In an embodiment, theserver supply manifold 105 is positioned below the power distributionbus 129.

In an embodiment, the coolant management unit 207 includes a firstblocking panel 201, a second blocking panel 203 and a third blockingpanel 205 to prevent impact from leaked fluid. In an embodiment, thefirst blocking panel 201 is on the top of the coolant management unit207. In an embodiment, the first blocking panel 201 is inserted into theserver chassis 209 to prevent the leaked fluid from the top. In anembodiment, the second blocking panel 203 is positioned between thepower distribution bus 129 and the server supply manifold 105 to preventa leakage from connectors. In an embodiment, the third blocking panel205 is on the bottom of the coolant management unit 207. In anembodiment, the third blocking panel 205 is inserted into the serverchassis 209 to prevent internal leaked fluid traveling outside.

FIG. 3 shows a top view of a rack design 300 according to certainembodiments of the application. In particular, FIG. 3 shows the designof the TPM 207 in the rack functioning with the blade servers. In anembodiment, connections include the fluid connections, and powerconnections. The communication is designed using the rack controller301, which is located in the rack. For example, the temperature sensorssuch as the ones measuring the chip temperature, T_chips 303 are sent torack controller 301 through the server BMC. In an embodiment, the rackcontroller 301 communicates with individual coolant management unitcontroller (e.g., 117). In an embodiment, the design 300 is to ensurethe T_chips 303 can be received by coolant management unit 207 in acertain control strategy design.

Each server blade would include a supply connector to connect with acorresponding server supply connector on the server supply manifold ofthe coolant management unit. Each server blade would include areturn/vapor connector to connect with a corresponding server returnconnector on the server return manifold of the coolant management unit.Each server blade would include a power interface to connect with thepower distribution bus of the coolant management unit to receive power.When a server blade is inserted into a server blade slot of a serverchassis, these connectors will connect with the corresponding connectorsof the coolant management unit, for example, automatically via blindmated and dripless connections.

In an embodiment, the power distribution bus includes power connectors309 to connect with servers 307. In an embodiment, the server supplymanifold includes liquid connectors 313 to connect with servers 307. Inan embodiment, the server return manifold includes vapor connectors 311to connect with servers 307.

In an embodiment, the liquid supply (i.e., rack supply manifold 101) andmain return (i.e., rack return manifold 103) are located at the rearside of the TPM 207. These two units 101, 103 are added to the rackafter the TPM 207 is added. The connection requires a liquid loopconnection where the pump is on, and vapor loop connection where thevapor pressure is on.

In an embodiment, the one or more sensors include one or moretemperature sensors to measure corresponding temperature of the server(e.g., 307 a, 307 b, 307 c, 307 d). In an embodiment, the controller 117is coupled to a communication port connected with a rack managementcontroller (RMC) 301. For example, the RMC 301 receives information ofthe corresponding server temperature from the controller 117.

FIG. 4 shows a rear view of rack integration 400 according to anembodiment of the application. In particular, FIG. 4 shows a rack leveldesign 400 with several blade servers installed. In an embodiment, theblade server includes vapor and liquid connections as well as the powerconnections. In addition, the server BMC 411 can communicate with theRMC 403 for the TPM controller 405 to be able to collect individualtemperature information.

In an embodiment, several TPMs (e.g., 407 a, 407 b, 407 c) are installedon the rack 401 and each of the TPM 407 is serving several bladeservers. In an embodiment, the design 400 may be varying, sincedifferent TPM 407 can be used for different groups of servers as well asserver configurations, on a same rack or different racks. Note thatagain, the terms of two-phase module or TPM and coolant management unitare interchangeable terms throughout this application.

FIG. 5 shows a perspective view of a system 500 according to anembodiment of the application. In particular, FIG. 5 shows that the rack505 is populated with several groups of blade servers (501 a, 501 b, 501c) connected with their respective TPMs (503 a, 503 b, 503 c). In anembodiment, each group of blade servers (501 a, 501 b, 501 c) isfunctioning with a respective TPM 503. In an embodiment, the rackmounted fluid liquid supply and main return are added to the rear sideof the racks once the TPMs (503 a, 503 b, 503 c) are populated. In anembodiment, the detailed operation may enable the blade servers (501 a,501 b, 501 c) to be installed and uninstalled from the rack 505 withoutany impact on other systems.

In addition, a TPM unit 503 can be individually installed anduninstalled without any impact on the rack liquid supply and mainreturn, since the connections are through flexible hoses. In anembodiment, the current design 500 enables an efficient control strategyon the fluid system since each of the individual TPM 503 are separatelycontrolled. In an embodiment, even though multiple TPMs (503 a, 503 b,503 c) are sharing the rack liquid supply and main return manifolds, theindividual controller (not shown) as well as the corresponding sensorsinput allows a robust localized control for groups of blade servers (501a, 501 b, 501 c).

FIG. 6 is block diagram illustrating an electronic rack according to oneembodiment. Electronic rack 1200 may represent any of the electronicracks as described throughout this application. According to oneembodiment, electronic rack 1200 includes, but is not limited to, heatexchanger 1211, rack management unit (RMU) 1202, and one or more serverchassis 1203A-1203E (collectively referred to as server chassis 1203).Server chassis 1203 can be inserted into an array of server slots (e.g.,standard shelves) respectively from frontend 1204 or backend 1205 ofelectronic rack 1200. Each server chassis may include one or more bladeslots to receive one or more server blades. Each server blade representsone or more servers therein. For each of the server chassis, a TPMmodule is mounted in the rear end of the rack. When a server blade isinserted from the frontend, the liquid/vapor connectors and the powerconnector of the server blade can connect with the corresponding TPMmodule. The TPM module may be coupled to the rack manifold, for example,via flexible hoses, as described above.

Note that although there are five server chassis 1203A-1203E shown here,more or fewer server chassis may be maintained within electronic rack1200. Also note that the particular positions of heat exchanger 1211,RMU 1202, and/or server chassis 1203 are shown for the purpose ofillustration only; other arrangements or configurations of heatexchanger 1211, RMU 1202, and/or server chassis 1203 may also beimplemented. In one embodiment, electronic rack 1200 can be either opento the environment or partially contained by a rack container, as longas the cooling fans can generate airflows from the frontend to thebackend.

In addition, for at least some of the server chassis 1203, an optionalfan module (not shown) is associated with the server chassis. Each ofthe fan modules includes one or more cooling fans. The fan modules maybe mounted on the backend of server chassis 1203 or on the electronicrack to generate airflows flowing from frontend 1204, traveling throughthe air space of the server chassis 1203, and exiting at backend 1205 ofelectronic rack 1200.

In one embodiment, heat exchanger 1211 may be a liquid-to-liquid heatexchanger. Heat exchanger 1211 includes a first loop with inlet andoutlet ports having a first pair of liquid connectors coupled toexternal liquid supply/return lines 1231-1232 to form a primary loop.The connectors coupled to the external liquid supply/return lines1231-1232 may be disposed or mounted on backend 1205 of electronic rack1200. The liquid supply/return lines 1231-1232, also referred to as roomliquid supply/return lines, may be coupled to an external coolingsystem.

In addition, heat exchanger 1211 further includes a second loop with twoports having a second pair of liquid connectors coupled to rack manifold1225 to form a secondary loop, which may include a supply manifold (alsoreferred to as a rack liquid supply line or rack supply manifold) tosupply cooling liquid to server chassis 1203 and a return manifold (alsoreferred to as a rack liquid return line or rack return manifold) toreturn warmer liquid back to heat exchanger 1211. Note that heatexchanger 1211 can be any kind of heat exchangers commercially availableor customized ones. Thus, the details of heat exchanger 1211 will not bedescribed herein.

Each of server chassis 1203 may include one or more informationtechnology (IT) components (e.g., electronic devices such as processors,memory, and/or storage devices). In one embodiment, in at least some ofthe server chassis 1203, an electronic device may be attached to a coldplate. The cold plate includes a liquid distribution channel to receivecooling liquid from the rack liquid supply line of rack manifold 1225.The cooling liquid performs heat exchange from the heat generated fromthe electronic device attached thereon. The cooling liquid carrying theexchanged heat is returned to the rack liquid return line of rackmanifold 1225 and back to heat exchangers 1211.

In another embodiment, some of the server chassis 1203 may include animmersion tank containing immersion cooling liquid therein. Theelectronic devices of the corresponding server(s) are at least partiallysubmerged into the immersion cooling liquid. The immersion coolingliquid may be dielectric cooling fluid, which may be circulated betweenthe immersion tanks and heat exchanger 1211. The cooling liquid may be asingle-phase cooling liquid or two-phase cooling liquid (also referredto as phase-change cooling liquid). The two-phase cooling liquidevaporates from a liquid form into a vapor form when the temperature ofthe cooling liquid is above a predetermined temperature threshold (e.g.,the boiling point of the cooling liquid). The vapor flows upstream viathe vapor line from the corresponding server chassis to heat exchanger1211. Heat exchanger 1211 may include a condenser to condense the vaporfrom the vapor form back to the liquid form, where the cooling liquid isthen supplied back to the server chassis.

Note that some of the server chassis 1203 may be configured withsingle-phase liquid cooling, while other server chassis may beconfigured with two-phase liquid cooling. Even within a single serverchassis, some of the IT components may be configured with single-phaseliquid cooling, while other IT components may be configured withtwo-phase liquid cooling. Rack manifold 1225 may include a first rackmanifold for single-phase cooling and a second rack manifold fortwo-phase cooling to be coupled to the same or different server chassisfor different types of cooling. Some of the server chassis 1203 may beconfigured with regular liquid and air cooling, while other serverchassis may be configured with immersion cooling.

Some of the IT components may perform data processing tasks, where theIT components may include software installed in a machine-readablemedium such as a storage device, loaded into a memory, and executed byone or more processors to perform the data processing tasks. Serverchassis 1203 may include a host server (referred to as a host node)coupled to one or more compute servers (also referred to as computingnodes). The host server (having one or more central processing units orCPUs) typically interfaces with clients over a network (e.g., Internet)to receive a request for a particular service such as storage services(e.g., cloud-based storage services such as backup and/or restoration),executing an application to perform certain operations (e.g., imageprocessing, deep data learning algorithms or modeling, etc., as a partof a software-as-a-service or SaaS platform). In response to therequest, the host server distributes the tasks to one or more of thecomputing nodes or compute servers (having one or more graphics/generalprocessing units or GPUs) managed by the host server. The computeservers perform the actual tasks, which may generate heat during theoperations.

Electronic rack 1200 further includes optional RMU 1202 configured toprovide and manage power supplied to servers 1203 and heat exchanger1211. RMU 1202 may be coupled to a power supply unit (not shown) tomanage the power consumption of the power supply unit. The power supplyunit may include the necessary circuitry (e.g., an alternating current(AC) to direct current (DC) or DC to DC power converter, battery,transformer, or regulator, etc.) to provide power to at least some ofthe remaining components of electronic rack 1200.

In one embodiment, RMU 1202 includes optional optimization module 1221and rack management controller (RMC) 1222. RMC 1222 may include amonitor to monitor operating status of various components withinelectronic rack 1200, such as, for example, computing nodes 1203, heatexchanger 1211, and the fan modules. Specifically, the monitor receivesoperating data from various sensors representing the operatingenvironments of electronic rack 1200. For example, the monitor mayreceive operating data representing temperatures of the processors,cooling liquid, and airflows, which may be captured and collected viavarious temperature sensors. The monitor may also receive datarepresenting the fan power and pump power generated by one or more fanmodules and liquid pumps, which may be proportional to their respectivespeeds. These operating data are referred to as real-time operatingdata. Note that the monitor may be implemented as a separate modulewithin RMU 1202.

Based on the operating data, optimization module 1221 performs anoptimization using a predetermined optimization function or optimizationmodel to derive a set of optimal fan speeds for the fan modules and anoptimal pump speed for a liquid pump, such that the total powerconsumption of the liquid pump and the fan modules reaches minimum,while the operating data associated with the liquid pump and coolingfans of the fan modules are within their respective designedspecifications. Once the optimal pump speed and optimal fan speeds havebeen determined, RMC 1222 configures the liquid pump and cooling fans ofthe fan modules based on the optimal pump speeds and fan speeds.

In the foregoing specification, embodiments of the invention have beendescribed with reference to specific exemplary embodiments thereof. Itwill be evident that various modifications may be made thereto withoutdeparting from the broader spirit and scope of the invention as setforth in the following claims. The specification and drawings are,accordingly, to be regarded in an illustrative sense rather than arestrictive sense.

What is claimed is:
 1. A coolant management unit for liquid cooling,comprising: a server supply manifold to be coupled to a rack supplymanifold to receive cooling fluid from a cooling fluid source, whereinthe server supply manifold is to distribute the cooling fluid to one ormore server blades of a server chassis of an electronic rack, whereinthe coolant management unit is positioned on a rear side of the serverchassis; a server return manifold to be coupled to a rack returnmanifold, wherein the server return manifold is to receive vapor fromthe one or more server blades, wherein the cooling fluid is two-phasecooling fluid to extract heat from one or more servers and to evaporateinto the vapor into the server return manifold, wherein the vapor istransmitted to an external condenser via the rack return manifold to becondensed back to a liquid form; a power distribution bus to distributepower to the one or more servers; and a controller to control a fluidpump coupled to the server supply manifold based on one or more signalsreceived from one or more sensors.
 2. The coolant management unit ofclaim 1, wherein the one or more sensors include a pressure sensorcoupled to the server return manifold to measure a pressure of vapor. 3.The coolant management unit of claim 2, wherein the pressure sensor iscoupled with the server return manifold including a vapor connector forconnecting with the rack return manifold.
 4. The coolant management unitof claim 1, wherein the one or more sensors include a leakage sensor todetect leakage of the cooling fluid.
 5. The coolant management unit ofclaim 1, wherein the one or more sensors include a power sensor coupledto the power distribution bus to detect power.
 6. The coolant managementunit of claim 1, further comprising a communication port to be connectedwith a rack management controller (RMC) of the electronic rack, whereinthe controller is configured to communicate with the RMC via thecommunication port.
 7. The coolant management unit of claim 6, whereinthe controller receives server temperature information from the RMC. 8.The coolant management unit of claim 1, wherein the server supplymanifold includes one or more liquid sub-ports connected withcorresponding liquid ports of the one or more server blades, and whereinthe server return manifold includes a vapor port connected with the rackreturn manifold.
 9. The coolant management unit of claim 1, wherein thepower distribution bus is positioned between the server return manifoldand the server supply manifold.
 10. The coolant management unit of claim1, further comprising a first blocking panel, a second blocking panel,and a third blocking panel to prevent impact from leaked fluid.
 11. Thecoolant management unit of claim 10, wherein the first blocking panel isdisposed on the top of the coolant management unit and inserted into theserver chassis to prevent the leaked fluid from the top.
 12. The coolantmanagement unit of claim 10, wherein the second blocking panel ispositioned between the power distribution bus and the server supplymanifold to prevent a leakage from connectors.
 13. The coolantmanagement unit of claim 10, wherein the third blocking panel is on thebottom of the coolant management unit and inserted into the serverchassis to prevent internal leaked fluid traveling outside.
 14. A serverchassis of an electronic rack, comprising: one or more server slots toreceive one or more server blades; and a coolant management unit forproviding liquid cooling to the server blades, the coolant managementunit comprising: a server supply manifold to be coupled to a rack supplymanifold to receive cooling fluid from a cooling fluid source, whereinthe server supply manifold is to distribute the cooling fluid to the oneor more server blades of the server chassis, wherein the coolantmanagement unit is positioned on a rear side of the server chassis; aserver return manifold to be coupled to a rack return manifold, whereinthe server return manifold is to receive vapor from the one or moreserver blades, wherein the cooling fluid is two-phase cooling fluid toextract heat from one or more servers and to evaporate into the vaporinto the server return manifold, wherein the vapor is transmitted to anexternal condenser via the rack return manifold to be condensed back toa liquid form; a power distribution bus to distribute power to the oneor more servers; and a controller to control a fluid pump coupled to theserver supply manifold based on one or more signals received from one ormore sensors.
 15. The server chassis of claim 14, wherein the one ormore sensors include a pressure sensor coupled to the server returnmanifold.
 16. The server chassis of claim 14, wherein the one or moresensors include a leakage sensor to detect leakage.
 17. The serverchassis of claim 14, wherein the one or more sensors include a powersensor coupled to the power distribution bus.
 18. An electronic rack,comprising: a plurality of server chassis arranged in a stack, eachserver chassis having one or more server slots to receive one or moreserver blades; and a plurality of coolant management units, eachcorresponding to one of the plurality of server chassis for connectingthe server chassis to provide liquid cooling the one or more serverblades of the corresponding server chassis, each coolant management unitcomprising: a server supply manifold to be coupled to a rack supplymanifold to receive cooling fluid from a cooling fluid source, whereinthe server supply manifold is to distribute the cooling fluid to the oneor more server blades of the server chassis, wherein the coolantmanagement unit is positioned on a rear side of the server chassis; aserver return manifold to be coupled to a rack return manifold, whereinthe server return manifold is to receive vapor from the one or moreserver blades, wherein the cooling fluid is two-phase cooling fluid toextract heat from one or more servers and to evaporate into the vaporinto the server return manifold, wherein the vapor is transmitted to anexternal condenser via the rack return manifold to be condensed back toa liquid form; a power distribution bus to distribute power to the oneor more servers; and a controller to control a fluid pump coupled to theserver supply manifold based on one or more signals received from one ormore sensors.
 19. The electronic rack of claim 18, wherein the one ormore sensors include a leakage sensor to detect leakage.
 20. Theelectronic rack of claim 18, wherein the one or more sensors include apower sensor coupled to the power distribution bus.